1. Field of the Invention
This invention relates generally to a moving coil pickup cartridge and is directed more particularly to a pickup cartridge of a stereophonic type having a novel magnetic circuit.
2. Description of the Prior Art
In general, a moving coil pickup cartridge is formed of a magnet, a first pole piece fixed to, for example, an N-pole surface of the magnet, a second pole piece fixed to an S-pole surface of the magnet, a magnetic gap established between the first and second pole pieces, and detecting coils for left and right channels located in the magnetic gap with the positional relation of 90.degree. with each other. This kind of the cartridge also has a coil holder with the shape of a disc a part of whose peripheral surface faces the magnetic gap. A cantilever is extended from the central portion of the coil holder, and the detecting coils are respectively wound on projections planted on the outer periphery of the coil holder at the symmetrical positions with the above angles of 90.degree..
Since, in such a prior art moving coil pickup cartridge, the equivalent mass of the vibrating member (coil holder including the cantilever and detecting coils) and so on is great, the generating operation of the respective detecting coils in the magnetic field is low and also the conversion efficiency is poor. Further, in view of making the cartridge, the works to wind the coils are rather complicated and also scattering is easily caused in the characteristics of products.